The present invention relates generally to relief valves of the type controlling discharge from a pressurized vessel to a drain line and, more particularly, to a relief valve having a coupling for interconnecting the relief valve to the drain line.
As is known, conventional fluid systems are equipped with relief valves for controlling discharge from a pressurized vessel to a drain line in response to a predetermined pressure and/or thermal condition. Such relief valves typically include a valve body that has an inlet interconnectable to the pressurized vessel, an outlet adapted for connection to the drain line, and a valve mechanism for controlling flow from the inlet to the outlet in response to the occurrence of one of the predetermined conditions. Typically, the inlet and outlet portions of the valve body are threaded for threaded engagement with mating couplings associated with the pressurized vessel and the drain line. A disadvantage to this type of valve body is that the threaded outlet may be plugged by a threaded plug member. In such a situation, the plugged outlet prevents the relief valve from performing its primary function of allowing discharge to escape from the pressurized vessel in response to the occurrence of one of the predetermined pressure and/or thermal conditions. As such, the resulting build up of pressure within the pressurized vessel and/or within the relief valve may exceed design specifications and cause a failure in the system.
While conventional relief valves perform satisfactorily when unrestricted, the need exists to develop a relief valve having a drain line coupling that inhibits the valve's outlet from being plugged or restricted.